A typical putter has an elongated head mounted on a shaft. One side of the head provides a face, generally parallel with the long axis of the head, for hitting the ball. With the bottom of the putter head lying flat on a level surface, the face may be vertical or tilted back a slight angle, called the loft of the putter, often between about 2 and 4 degrees. The shaft is attached to the putter head and extends from the head in a plane that is generally parallel to the long axis of the head and the face of the putter. With the bottom of the putter head again lying flat on a level surface, the shaft is angled upwards from the horizontal at an angle, called the lie of the putter, of between about 68 and 78 degrees. Some variations from this typical configuration will be discussed below.
U.S. Pat. No. 4,881,737 describes a putter with a cylindrical head. The side of the cylinder is used to contact the ball so the face is convex rather than flat. The shaft may be inclined between 16 degrees and 22 degrees relative to a vertical plane normal to the longitudinal centerline of the head. The inclination of the shaft may be varied because the end of the shaft is fitted with a partial cylinder, mounted with its central axis perpendicular to the shaft, that can rotate through the angles of inclination mentioned above in a slot in the head. A desired angle of inclination is fixed by screwing a wedge block into the slot to clamp the end of the shaft into the slot.
U.S. Pat. No. 5,348,295 describes a putter with an elongated head having a flat face. The end of the shaft has a sphere that is mounted in one of two pockets in the head. Each pocket prevents the sphere from leaving the head but permits the shaft to rotate through a range of lie angles. One pocket allows the shaft to be positioned relative to the face as appropriate for left handed golfers, while the other pocket allows the shaft to be positioned for right handed golfers. With the sphere in either pocket, set screws through the head are tightened against the sphere to hold the shaft at a desired lie.
U.S. Pat. No. 5,390,920 describes a putter with a head having a flat face at one side and bullet shaped weights protruding from the other side. A sphere on the end of the shaft is mounted in a cylindrical bore through the head. An annular shoulder in the bore prevents the sphere from coming out of the bore through the top of the head. A screw threaded into the bore from the bottom of the head locks the sphere in place between the annular shoulder and the top of the screw. The screw has a lower portion that breaks off as the screw is tightened in place to permanently fix the shaft at a desired lie and loft angle. The annular shoulder may be sharpened to provide a biting engagement with the sphere.
U.S. Pat. No. 5,692,969 describes a putter with a cylindrical head and convex face. The end of the shaft has a ball or cylinder that fits into a bore in the head. The top of the bore has a shoulder to engage the ball but also opens to the top of the head through an elongated opening. The elongated opening allows the shaft to pivot through lie angles of between 30 and 90 degrees while preventing the shaft from pivoting about the longitudinal axis of the head. A resilient plastic or aluminum retainer is inserted into the bore from the bottom of the head and held against the ball by a locking member threaded into the bore. A golfer alters the angle of the shaft relative to the head by applying weight to the resilient retainer to disengage the ball from the shoulder of the bore. An alternate embodiment has an offset shaft. Another alternate embodiment has a head with a flat face.